2 research outputs found
Effects of Structure Variation on Solution Properties of Hydrotropes: Phenyl versus Cyclohexyl Chain Tips
The physicochemical behavior of the phenyl-<i>n</i>-alkanoate
(PhenCx) and cyclohexyl-<i>n</i>-alkanoate (CyclohexCx)
series has been investigated, supporting previous work on the understanding
of hydrotropes (Hopkins Hatzopoulos, M.; Eastoe, J.; Dowding, P.J.;
Rogers, S. E.; Heenan, R.; Dyer, R. <i>Langmuir</i> <b>2011</b>, <i>27</i>, 12346â12353). Electrical
conductivity, surface tension, <sup>1</sup>H NMR, and small-angle
neutron scattering (SANS) were used to study adsorption and aggregation
in terms of critical aggregation concentration (cac). The PhenCx series
exhibited very similar d logÂ(cac)/d<i>n</i> to <i>n</i>-alkylbenzoates (CnBenz), exhibiting two branches of behavior, with
a common inflection point at four linear carbons, whereas the CyclohexCx
series showed no break point. Electrical conductivity and <sup>1</sup>H NMR concentration scans indicate a difference in physicochemical
behavior between higher and lower homologues in both the PhenCx and
CyclohexCx series. Surface tension measurements with compounds belonging
to either group gave typical Gibbs adsorption profiles, having d logÂ(cac)/d<i>n</i> curves consistent with limiting headgroup areas in the
region of (35â55 Ă
<sup>2</sup>) indicating monolayer formation.
SANS profiles showed no evidence for aggregates below the electrical
conductivity determined cac values, inferring an âonâoffâ
mode of aggregation. Analyses of SANS profiles was consistent with
charged ellipsoidal aggregates, persisting from lower through to higher
homologues in both the PhenCx and CyclohexCx series
Effects of Structure Variation on Solution Properties of Hydrotropes: Phenyl versus Cyclohexyl Chain Tips
The physicochemical behavior of the phenyl-<i>n</i>-alkanoate
(PhenCx) and cyclohexyl-<i>n</i>-alkanoate (CyclohexCx)
series has been investigated, supporting previous work on the understanding
of hydrotropes (Hopkins Hatzopoulos, M.; Eastoe, J.; Dowding, P.J.;
Rogers, S. E.; Heenan, R.; Dyer, R. <i>Langmuir</i> <b>2011</b>, <i>27</i>, 12346â12353). Electrical
conductivity, surface tension, <sup>1</sup>H NMR, and small-angle
neutron scattering (SANS) were used to study adsorption and aggregation
in terms of critical aggregation concentration (cac). The PhenCx series
exhibited very similar d logÂ(cac)/d<i>n</i> to <i>n</i>-alkylbenzoates (CnBenz), exhibiting two branches of behavior, with
a common inflection point at four linear carbons, whereas the CyclohexCx
series showed no break point. Electrical conductivity and <sup>1</sup>H NMR concentration scans indicate a difference in physicochemical
behavior between higher and lower homologues in both the PhenCx and
CyclohexCx series. Surface tension measurements with compounds belonging
to either group gave typical Gibbs adsorption profiles, having d logÂ(cac)/d<i>n</i> curves consistent with limiting headgroup areas in the
region of (35â55 Ă
<sup>2</sup>) indicating monolayer formation.
SANS profiles showed no evidence for aggregates below the electrical
conductivity determined cac values, inferring an âonâoffâ
mode of aggregation. Analyses of SANS profiles was consistent with
charged ellipsoidal aggregates, persisting from lower through to higher
homologues in both the PhenCx and CyclohexCx series